UNIX for Dummies Questions & Answers

We have purchased four intels xeon processors

Intel® Xeon® Processor E7530 (12M Cache, 1.86 GHz, 5.86 GT/s Intel® QPI) with SPEC Code(s) SLBRJ

As per the specification each cpu has 6 cores therefore we have 24 cores (considering 4 cpus).
Now how would i calculate the number of vcpus that can be used while visualization?
This will help use to capacity planning.

There's no hard rule on this. Some people over commit.. so the sum total of VM resources is greater than actual physical resources. Usually, one place where this is done is with regards to CPUs. BUT... if your VMs REALLY need a whole bunch of CPU resources, it's possible that you'll reach the limits of what you can actually give and have a "good" performing platform. IMHO, it's pretty safe to say that we waste about 50% of CPU resources (in general, the number is usually much, much higher). So you could use that for a very conservative number of total CPUs you can dole out. And don't discount the hyperthreads... they do help out as well...

If your plan is to virtualize large scale servers (e.g. 4 CPUs + 8G+ memory) ... I think that's a BAD plan. Virtualization is most effective when talking about smaller footprint machines. Then the scalability can be VERY large.. and you can really over commit (but again, there is no RULE).